A compound of the following formula is known as an active ingredient of a stabilizer for polymers such as thermoplastic polymers (e.g., polybutadiene, etc.) and the like, and it is also known that this compound is obtained in the form of a powdery crystal (see, e.g., patent document 1).

A polymer stabilizer containing the above-described compound as an active ingredient is dissolved in a hydrocarbon solvent, then, compounded, as a dissolved material, in a polymer, to produce a polymer composition.    (Patent document 1) JP-A No. 10-273494